Natural selection. darwin hypothesized that there requisites for natural selection to occur and that there are definite steps to natural selection. note the two models seen here. both of the models illustrate an important requisite for natural selection. that is: a) sexual reproduction must occur. b) there is survival of the fittest. c) variation in the population exists. d) genetic sameness reduces the chances of natural selection.

The dipole moment of the water molecule (h2o) is 6.17x10^-30 c.m. consider a water molecule located at the origin whose dipole moment p points in the +x-direction. a chlorine ion ( of charge-1.60x10^-19c , is located at x=3.00x10^-9m . assume that is much larger than the separation d between the charges in the dipole, so that the approximate expression for the electric field along the dipole axis can be used. a) find the magnitude of the electric force that the water molecule exerts on the chlorine ion. b) what is the direction of the electric force. -x-direction or +x-direction c) is this force attractive or repulsive?